Pros:

- Strong carry protection during laning and teamfight;

- Can allow a counter-pick, since they won't expect the lee support.

- Very reactive and quite rewarding and fun champions.

- Early damage pressure pre-6, and kill assured lvl6;

- Good mobility, warding is the most useful thing on lee, so you are the team vision

Cons:

- Not so easy to play, need to master the blind monk.

- Early AP do hurt, so make sure to proc the relic shield;

- You need to be very reactive on shielding or engaging;

- Melee range, harass with q and go in when you can safeguard safely.

Work well with assassin or burst champion on your team, yasuo as example as you can take lonely pick easily.

Since lee have a jungle soul, he work well with mostly all jungler and have some stuff to easily bate or engage a gank.